Question: $ C = \left[\begin{array}{rrrr}4 & 2 & 3 & 2 \\ -2 & 0 & 2 & -1 \\ 0 & 2 & -2 & -2\end{array}\right]$ What are the dimensions of matrix $ C$ ?
Answer: The first dimension is the number of rows in the matrix. How many rows does $ C$ have? The second dimension is the number of columns in the matrix. How many columns does $ C$ have? So, $ C$ is a 3 $\times$ 4 matrix.